MINNEAPOLIS — Joe Berger remembers the feeling. It was February 2005 and Berger, along with hundreds of other N.F.L. hopefuls, was at the combine, the league’s annual scouting carnival. Many of the players were nervous or anxious, fretting about their bench-press repetitions or their sprint times. Berger, on the other hand, mostly felt bloated.

“I just never stopped drinking,” he recalled recently. “I chugged everything. Gatorade, water, whatever — all I wanted in life was to make 300 pounds.”

Buoyed (and admittedly somewhat distended) from his hyper hydration, Berger did, in fact, swell to 300 pounds — “303!” he said — which, for a college lineman looking to play in the N.F.L., was the generally accepted bare minimum. But since then, while his colleagues on the line have often ballooned to weights closer to 320 pounds or more (yes, sometimes a lot more), Berger has stayed put. Now in his sixth season with the Vikings and 12th professional season over all, Berger proudly still weighs 305 pounds.

“One year I tried going up to 320,” he said. “It felt like I was in a fat suit. I couldn’t move.”

As a result of enhanced nutrition techniques, changing offensive styles and adjustments to football’s rules, Berger and his brethren of undersize linemen appear to be a growing demographic in the N.F.L. And they are generally happy to embrace their roles as the pygmy elephants of their sport, the baby grand pianos of the game: little, but not that little.

“We’re only small in this particular line of work,” said Chris Chester, a 303-pound guard for the Atlanta Falcons.

Calculating average weights for N.F.L. lines is tricky, because injuries are frequent and depth charts fluid. But by one recent compilation, the Falcons’ average weight of about 304 pounds is roughly 10 pounds lighter than the league median and 20 pounds lighter than Washington’s, the league’s heaviest group.

Extrapolating the efficacy of a lighter line can be murky, too — rating line play in general is difficult, since performances are not as easily quantified as they are at skill positions — but so far this season, several teams with slimmer lines are thriving on offense.

“If you can find someone who is 360 and runs like a gazelle, then sure, take him,” said Alex Mack, Atlanta’s 305-pound center. “But in most cases, that player doesn’t exist. So if you want to do a particular thing with your offense, you need to go light.”

For the Falcons, lighter linemen fit their offensive scheme. As Mack described it, Atlanta is always trying to “get, or threaten, the edge” of the field, as opposed to simply bulling through manufactured spaces in the middle.

That means the offensive line — two tackles, two guards and a center — is often asked to move side to side, shifting into different areas or sprinting to get in front of a quick-developing play and an even quicker ball carrier.

In the first quarter of a game, that can be challenging enough for a man carrying a lot of weight. By the fourth quarter, particularly if a team has been playing a hurry-up offense, it can be nearly impossible.

“I honestly think part of it comes from the number of college teams who are playing fast,” said Jeremiah Sirles, a guard for the Vikings who weighs, he said, “just under 315.”

Sirles continued: “You have to be in good shape just to keep up with the number of plays. If you’re dragging, you can’t block anyone.”

The drawback, of course, is that lighter offensive linemen can more often get bowled over — trucked, in the vernacular — by heavier defensive rushers. But by using plays that are often run to the edge, an offense forces the defensive players to hesitate for a moment at the snap to make sure they don’t overrun the play, giving the offensive linemen a chance to “get off the ball” first, or make the initial blocking move that gives them an advantage.

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The former Cowboy Nate Newton had the rare combination of speed and size.CreditBrian Bahr/Getty Images

Tony Boselli, a former star lineman for the Jacksonville Jaguars, said he would not be surprised to see more teams begin to use lighter linemen in a copycat league like the N.F.L., but he noted that it was not really the weight that was important.

“It is the athleticism,” he said, noting that rules changes had made the N.F.L. a more offense-friendly league and had encouraged quicker, less physical play.

“There’s a certain cutoff,” he added. “You can’t be too light. I’d say the minimum is 285. I don’t care how big you are over that as long as you can move.”

Plenty of teams, of course, continue to stick to the long-tested formula of bigger being better when it comes to linemen. But it seems that size may be reaching a plateau. Other position groups, including defensive lines, have seen shifts toward valuing speed and quickness over sheer size, and so it follows that offensive lines would do the same.

“The bigger you are and the longer you are, the more space you take up and so it’s harder to get around you,” Boselli said. “That is never going to change. But coaches and personnel guys are seeing that there is more to it than that. What makes up that 310 pounds? What else is there?”

Boselli added that ideally a player would have a combination of size and speed. He pointed to Nate Newton — the former Dallas Cowboys lineman who played at 335 pounds and “didn’t look good without a shirt on but could really move” — as someone he would just “tell to go play.” But he acknowledged that such players were rare. “And now, many teams are putting speed ahead of size,” he said.

It is possible, too, that some teams are attracted to lighter linemen because of a market inefficiency. Michael Renner, a senior analyst for the advanced statistical service Pro Football Focus, said that offensive linemen were typically not a position group that had a direct correlation with a team’s overall success, but rather were an “amplifier” that could be molded — and compensated for — by how a team operated at the skill positions.

Because of that, Renner said, some teams may look to use the line as an area of economic value. And if a player “doesn’t match up to the expected traits of that position,” Renner said, “it generally means he earns a smaller salary than a player who does.”

In other words, smaller linemen can still generally be paid less, Renner said, “because everyone expects them to be bigger.”

A version of this article appears in print on , on Page SP1 of the New York edition with the headline: Growth in Smaller Linemen Follows Changes in the N.F.L.. Order Reprints | Today’s Paper | Subscribe